The present invention relates to the collection and characterization of residues, particularly to the collection of trace amounts of high explosives and chemical weapons residues for field analysis, and more particularly to a field-deployable, small, hand held, all-in-one device for efficient sampling, sample dissolution, and sample application to an analytical technique.
Over the last decade extensive efforts have been carried out for development methods for characterization of various chemicals, particularly for the characterization of high explosives, chemical weapons, and biological weapons. These activities have centered on the collection, isolation, and concentration of trace amounts of these chemical residues in air, soil, vegetation, swipe, and liquid samples. Considerable resources have been applied to developing consistent and reliable methods for field analysis of high explosives and chemical weapons related materials. For example, The Forensic Science Center (FSC) at the Lawrence Livermore National Laboratory (LLNL) has been developing new technology for the characterization of high explosives (HE) and chemical weapons (CW) in the field. These activities have centered on the collection, isolation, and concentration of trace amounts of HE, and CW residues in air, soil, vegetation, swipe and liquid samples. Considerable resources have been applied to developing consistent and reliable methods for the field analysis of HE and CW-related materials. Recently the FSC was contracted by the United States Army to take a priven laboratory technique, Thin Layer Chromatography (TLC), and bring it to field utilization to determine the chemical composition of propellants.
Solid Phase Microextraction (SPME) is a widely recognized approach for the collection of various chemical residues, and SPME fibers and syringes are commercially available. SPME requires no solvents, is sensitive to low nanogram signature species, and can be repeatedly used in the field for the characterization of complex samples. A significant attribute of SPME fibers is their exceedingly high collection efficiencies. No chemical pretreatment of solvent extraction are necessary when using SPME fibers with GC or GC-MS instrumentation. The SPME approach has been developed to point of field-deployment, as exemplified by co pending U.S. application Ser. No. 09/834,138 filed Apr. 2, 2001, entitled “Solid Phase Micro-extraction Field Kit”, assigned to the same assignee, and U.S. application Ser. No. 10/126,792, filed Apr. 18, 2002, entitled “Miniature Solid Phase Micro-extraction Holder”, assigned to the same assignee.
Due to the fragile nature of the SPME fiber, there is a need for a more robust approach to environmental sampling, particularly where the contamination has been deposited as a residue on a surface requiring swiping of the surface to obtain a sample. Accordingly, there still exists a need for the rapid analysis of samples containing, high explosive, chemical warfare, and other analytes of interest under field condition. Typically under field conditions, large numbers of samples are necessary from cordoned-off areas. Large sample collections of this type hinder any hope of expeditious analysis. Therefore, the development and use of a small had-held, all-in-one device for efficient sampling, sample dissolution, and sample application to an analytical technique, has been most desired by field analysts.
The present invention provides a solution to this need by utilizing a small, very robust sampling apparatus, with sample collection, sample dissolution, and sample application. The apparatus utilizing a wetted sampling sponge to collect, dissolve, and deposit a sample of interest for immediate or later instrumental analysis. The wetted sponge is retained before and after sampling in a hermetically sealed device which contains a measured amount of solvent. The device also contains a small pipette tip by which the dissolved sample can be squeezed out of the sponge into a vial for later anaylsis or directly applied to a thin layer chromatography for immediate analysis.